U.S. patent application number 14/779750 was filed with the patent office on 2016-02-25 for a hatschek process for the production of fiber cement plates.
This patent application is currently assigned to REDCO NV. The applicant listed for this patent is REDCO NV. Invention is credited to Bertrand Van Acoleyen.
Application Number | 20160052163 14/779750 |
Document ID | / |
Family ID | 48128145 |
Filed Date | 2016-02-25 |
United States Patent
Application |
20160052163 |
Kind Code |
A1 |
Van Acoleyen; Bertrand |
February 25, 2016 |
A HATSCHEK PROCESS FOR THE PRODUCTION OF FIBER CEMENT PLATES
Abstract
A Hatschek process for the production of profiled fiber cement
plates is provided. The process comprises the steps of: (i)
providing an endless fiber cement multilayered slab stacking at
least one monolayer of a first type having a first width and at
least one monolayer of a second type of monolayers having a second
width, the at least one monolayer of a second type of monolayers
extending in transverse direction beyond the at least one monolayer
of a first type of monolayer: (ii) accumulating at least one layer
of the endless fiber cement multilayered slab on a profiled
accumulator roll having a recess along at least part of its
circumference whereby the at least first monolayer is provided
within the recess;(iii) removing the accumulated slab from the
accumulator roll; and (iv) curing the uncured fiber cement
plate.
Inventors: |
Van Acoleyen; Bertrand;
(Kapelle-op-den-Bos, BE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
REDCO NV |
Kapelle-op-den-Bos |
|
BE |
|
|
Assignee: |
REDCO NV
Kapelle-op-den-Bos, BE
BE
|
Family ID: |
48128145 |
Appl. No.: |
14/779750 |
Filed: |
March 30, 2014 |
PCT Filed: |
March 30, 2014 |
PCT NO: |
PCT/EP2014/056386 |
371 Date: |
September 24, 2015 |
Current U.S.
Class: |
264/171.13 |
Current CPC
Class: |
B28B 1/526 20130101;
B28B 1/527 20130101 |
International
Class: |
B28B 1/52 20060101
B28B001/52 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 15, 2013 |
EP |
13163835.5 |
Claims
1. A Hatschek process for the production of profiled fiber cement
plates, comprising the steps of providing an endless fiber cement
multilayered slab (101) in a production direction (103) by stacking
at least one monolayer (105) of a first type of monolayer having a
first width (W1) in transverse direction (115) and at least one
monolayer (107, 109, 111) of a second type of monolayers having a
second width (W2) in said transverse direction, said first width
(W1) being less than said second width (W2), the at least one
monolayer (107) of a second type of monolayers extending in
transverse direction beyond the at least one monolayer (105) of a
first type of monolayer; accumulating at least one layer of said
endless fiber cement multilayered slab on a profiled accumulator
roll (117), said accumulator roll having a recess (125) in axial
direction (121) along at least part of its circumference (127),
whereby the at least first monolayer is provided within said
recess, thereby providing an accumulated slab (133); removing said
accumulated slab from the accumulator roll, thereby providing an
uncured, profiled fiber cement plate (130); and curing said uncured
fiber cement plate to provide said profiled fiber cement plate.
2. A Hatschek process according to claim 1, wherein the recess has
a depth of between 0.5 mm and 3 mm.
3. A Hatschek process according to claim 1, wherein the difference
between said width (W1) of said first type of monolayers in
transverse direction (115) and the width (W2) of said second type
of monolayers is at least 40 mm.
4. A Hatschek process according to claim 1, wherein said
multilayered slab further comprises n additional monolayers n being
an integer of at least 1, said width of each of said n additional
monolayers in transversal direction is more than the first width,
and wherein each of said n additional monolayers extending in
transverse direction beyond the first monolayer.
5. A Hatschek process according to claim 4, wherein said n
additional monolayers are monolayers of said second type of
monolayers.
6. A Hatschek process according to claim 1, wherein said recess has
a trapezoid shape, the length of the radial projection of each of
the legs of said trapezoid shape on the axis of said accumulator
roll is in the range of 2 to 20 mm.
7. A Hatschek process according to claim 1, wherein said
multilayered slab further comprises m additional monolayers, said m
monolayers being monolayers of said first type of monolayers.
8. A Hatschek process according to claim 1, wherein said
multilayered slab consists of 2 to 8 monolayers.
9. A Hatschek process according to claim 1, wherein the at least
one monolayer of a first type of monolayer has a thickness
different from the thickness of the at least one monolayer of a
second type of monolayers.
10. A Hatschek process according to claim 1, wherein each of said
monolayers is provided by accumulating fiber cement slurry on a
rotating sieve drum and removing said accumulated fiber cement
slurry from said rotating sieve drum as a monolayer, the width of
said first type of monolayer in transverse direction being provided
by obstructing at least part of the sieve at the outer ends in
axial direction of the rotating sieve drum.
11. A Hatschek process according to claim 1, wherein each of said
monolayers is provided by accumulating fiber cement slurry on a
rotating sieve drum and removing said accumulated fiber cement
slurry from said rotating sieve drum as a monolayer, the width of
said first type of monolayers in transverse direction being
provided by removing the part of the accumulated fiber cement
slurry from the sieve, which parts extends beyond the width to be
provided.
12. A Hatschek process according to claim 11, wherein the slurry is
removed by spraying water to the slurry to be removed.
13. A Hatschek process according to claim 1, wherein said
accumulator roll has no recess (125) in axial direction (121) along
at least 40 mm of its circumference.
14. A Hatschek process according to claim 1, wherein said
accumulator roll having a recess (125) in axial direction (121)
along its complete circumference, the process further comprising
the use of a means to contact the at least one layer of said
endless fiber cement multilayered slab to the accumulator roll in
the recess at start of accumulation of the at least one layer of
said endless fiber cement multilayered slab on a profiled
accumulator roll.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to Hatschek processes for the
production of fiber cement plates, and fiber cement plates obtained
using such processes.
BACKGROUND OF THE INVENTION
[0002] Hatschek processes for the production of fiber cement plates
are well known in the art. Typically rectangular
parallelepiped-shaped plates are formed. To provide a profiled
shape, usually to provide tapered edges to the long sides of the
plate, the excess of cured fiber cement is grinded or cut away.
Attempts to overcome this extra process step of material removal,
which is relatively expensive, by accumulating uncured fiber cement
slab as multilayered slab form the Hatschek machinery on a profiled
accumulator roll. However the disadvantage is that the density and
hence the physical properties of the plate with tapered edges, is
different.
SUMMARY OF THE INVENTION
[0003] It is an object of the present invention to provide a
process for providing profiled fiber cement plates, having tapered
or beveled edges at at least two parallel sides of the plate, which
has less deviation in density across the plate in transversal
direction.
[0004] The above objective is accomplished by processes according
to the present invention.
[0005] According to a first aspect of the present invention, a
Hatschek process for the production of profiled fiber cement plates
is provided, the process comprising the steps of [0006] Providing
an endless fiber cement multilayered slab in a production direction
by stacking at least one monolayer of a first type of monolayer
having a first width (W1) in transverse direction (115) and at
least one monolayer of a second type of monolayers having a second
width (W2) in the transverse direction, the first width (W1) being
less than the second width (W2), the at least one monolayer of a
second type of monolayers extending in transverse direction beyond
the at least one monolayer of a first type of monolayer; [0007]
Accumulating at least one layer of the endless fiber cement
multilayered slab on a profiled accumulator roll, the accumulator
roll having a recess in axial direction along at least part of its
circumference, whereby the at least first monolayer is provided
within the recess, thereby providing an accumulated slab; [0008]
Removing the accumulated slab from the accumulator roll, thereby
providing an uncured, profiled fiber cement plate; [0009] Curing
the uncured fiber cement plate to provide the profiled fiber cement
plate.
[0010] With transverse direction is meant the direction
perpendicular to the production direction and perpendicular to the
plate surface.
[0011] The at least one monolayer of a second type of monolayers
extending in transverse direction beyond the at least one monolayer
of a first type of monolayer means that the borders in process
direction for the one or more monolayers of the second type of
monolayers extend beyond the corresponding borders in process
direction for the one or more monolayers of the first type of
monolayers in transversal direction.
[0012] The profiled fiber cement plate so obtained, has the
advantage that the density of the plate in transverse direction of
the plate varies to a less extent as would be the case when merely
a profiled accumulator roll were used. The density in the
transversal direction varies only little, the deviation being
usually less than 20%, or even is less than 15% of the average
density.
[0013] The profile that is given is a tapered of beveled profile at
both outer sides of the profiled fiber cement plate, wherein the
slope of the profile can be varied by appropriate selection of the
recess profile in the accumulator roll. The difference in thickness
of the plate from the middle section of the plate to the edge of
the plate may be up to 3 mm (millimeter), typically ranges up to 2
mm, and may be between 0.5 and 3mm, such as between 0.5 mm and 2mm,
such as between 1 mm and 2 mm.
[0014] According to some embodiments, the recess may have a depth
of between 0.5 mm and 3 mm. The recess, in axial direction
typically being a trapezoid shaped recess, may have a depth up to 3
mm (millimeter), typically ranging up to 2 mm, and may be between
0.5 mm and 2mm, such as between 1 mm and 2 mm. Trapezoid is to be
under stood as a quadrilateral having exactly one pair of parallel
sides.
[0015] According to some embodiments, the difference between the
width (W1) of the first type of monolayers in transverse direction
and the width (W2) of the second type of monolayers may be at least
40 mm.
[0016] Preferably the difference between the width W1 of the first
type of monolayers in transverse direction and the width W2 of the
second type of monolayers is at least 50 mm, e.g. at least 80
mm.
[0017] According to some embodiments, the multilayered slab further
comprises n additional monolayers, n being an integer of at least
1, the width of each of the n additional monolayers in transversal
direction may be more than the first width, and wherein each of the
n additional monolayers extending in transverse direction beyond
the first monolayer.
[0018] According to some embodiments, the n additional monolayers
may be monolayers of the second type of monolayers.
[0019] According to some embodiments, the recess may have a
trapezoid shape, the length of the radial projection of each of the
legs of the trapezoid shape on the axis of the accumulator roll is
in the range of 2 to 20 mm.
[0020] Preferably the length of the radial projection of each of
the legs of the trapezoid shape on the axis of the accumulator roll
is in the range of 5 to 15 mm, more preferred in the range of 10 to
15 mm.
[0021] According to some embodiments, the multilayered slab further
may comprise m additional monolayers, the m monolayers being
monolayers of the first type of monolayers.
[0022] According to some embodiments, the multilayered slab may
consist of 2 to 8 monolayers. Preferably the multilayered slab
consists of 2, 3, 4, 5, 6, 7 or 8 monolayers, though more
monolayers are possible.
[0023] It is understood that the sequence of layers with different
width may vary according to various patterns. As an example, the
layer first provided in production direction may be the monolayer
of the first type of monolayers with the smallest width, hence
being the at least one monolayer with width W1. Thereafter the
second and further layers in production direction sequence may all
be of the second type of monolayers with a width W2 and extending
in transversal direction beyond the first layer. Alternatively the
second and subsequent layers may gradually have increasing widths
in transversal direction, and each layer may extend in transversal
direction beyond all previously provided monolayers. Alternatively
the monolayer first provided in production direction may be the
layer with the maximum width, such as the at least one monolayer of
the second type of monolayers, the second and subsequent layers may
gradually have decreasing widths in transversal direction, and each
layer may be extended in transversal direction by all previously
provided monolayers. It is understood that any other sequence may
be used.
[0024] According to some embodiments, the at least one monolayer of
a first type of monolayer may have a thickness different from the
thickness of the at least one monolayer of a second type of
monolayers.
[0025] The thicknesses of each of the monolayers may vary from 0.1
to 0.6 mm, syuc as between 0.2 and 0.5 mm, such as between 0.3 to
0.5 mm. As an example, the thickness of the monolayer may be 0.4
mm.
[0026] By varying the density of the slurries, one can influence to
some extent the thickness of the monolayer when present in the
multilayered slab, optionally during accumulation on the
accumulator drum. This variation in density may facilitate the
production of slightly different fiber cement plates using one and
the same profiled accumulator drum.
[0027] According to some embodiments, each of the monolayers may be
provided by accumulating fiber cement slurry on a rotating sieve
drum and removing the accumulated fiber cement slurry from the
rotating sieve drum as a monolayer, the width of the first type of
monolayer in transverse direction being provided by obstructing at
least part of the sieve at the outer ends in axial direction of the
rotating sieve drum.
[0028] This obstruction can be obtained by providing a paint,
typically a water resistant paint to the zone of the sieve to be
prevented of accumulating slurry, or by providing a water
impermeable tape or liner.
[0029] Alternatively rotating sieve drums with different the axial
length of the rotating sieves may vary to provide the different
monolayer widths.
[0030] According to some embodiments, each of the monolayers may be
provided by accumulating fiber cement slurry on a rotating sieve
drum and removing the accumulated fiber cement slurry from the
rotating sieve drum as a monolayer, the width of the first type of
monolayers in transverse direction being provided by removing the
part of the accumulated fiber cement slurry from the sieve, which
parts extends beyond the width to be provided.
[0031] According to some embodiments, the slurry may be removed by
spraying water to the slurry to be removed.
[0032] According to some embodiments, the accumulator roll may have
no recess in axial direction along at least 40 mm of its
circumference. More preferably the accumulator roll has no recess
in axial direction along at least 50 mm of its circumference, even
along at least 100 mm or even along at least 150 mm.
[0033] The absence of the recess, typically along a minor part of
the circumference, allows the fresh multilayered slab to be picked
up by the accumulator roll after the former slab has been removed.
It is understood that the strip of uncured fiber cement plate where
the recess is not present, hence the profile of the plate is not
provided, will be cut. The cut material will be recycled to the
fiber cement slurry as is typically done in Hatschek processes.
[0034] According to some embodiments, the accumulator roll may have
a recess in axial direction along its complete circumference, the
process further comprising the use of a means to contact the at
least one layer of the endless fiber cement multilayered slab to
the accumulator roll in the recess at start of accumulation of the
at least one layer of the endless fiber cement multilayered slab on
a profiled accumulator roll.
[0035] Such means to contact the at least one layer of the endless
fiber cement multilayered slab to the accumulator roll in the
recess at start of accumulation may be a mechanical means, such as
a bar or roller, that is suitable to press the fresh multilayered
slab to at least part of recess along the circumference of the
accumulator roll.
[0036] The fiber cement slurry typically comprises water, process
or reinforcing fibers which both may be organic fibers (typically
cellulose fibers) or synthetic fibers (polyvynilalcohol,
polyacrilonitrile, polypropylene, polyamide, polyester,
polycarbonate, etc.), cement e.g. Portland cement, limestone,
chalk, quick lime, slaked or hydrated lime, ground sand, silica
sand flour, quartz flour, amorphous silica, condensed silica fume,
microsilica, metalkaolin, wollastonite, mica, perlite, vermiculite,
aluminum hydroxide, pigments, anti-foaming agents, flocculants, and
other additives.
[0037] The independent and dependent claims set out particular and
preferred features of the invention. Features from the dependent
claims may be combined with features of the independent or other
dependent claims, and/or with features set out in the description
above and/or hereinafter as appropriate.
[0038] The above and other characteristics, features and advantages
of the present invention will become apparent from the following
detailed description, taken in conjunction with the accompanying
drawings, which illustrate, by way of example, the principles of
the invention. This description is given for the sake of example
only, without limiting the scope of the invention. The reference
figures quoted below refer to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] FIG. 1 is a schematically view of a Hatschek process.
[0040] FIG. 2 is schematically view of an accumulator roll used in
a process according to the invention.
[0041] FIG. 3 is schematically view of an endless fiber cement
multilayered slab in a production direction according to the
invention.
[0042] FIG. 4 is schematically view of an accumulator roll on which
multiple layers of endless fiber cement multilayered slab are
accumulated, according to the invention.
[0043] FIG. 5 is schematically view of an uncured, profiled fiber
cement plate according to the invention.
[0044] FIGS. 6 and 7 are schematically views of a series of
rotating drum sieves as used in a process according to the present
invention.
[0045] FIG. 8 shows the density profile in transversal direction of
an uncured, profiled fiber cement plate according to the
invention.
[0046] FIGS. 9a to 9j are schematically views of endless fiber
cement multilayered slabs in a production direction according to
the invention.
[0047] The same reference signs refer to the same, similar or
analogous elements in the different figures.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0048] The present invention will be described with respect to
particular embodiments. It is to be noticed that the term
"comprising", used in the claims, should not be interpreted as
being restricted to the means listed thereafter; it does not
exclude other elements or steps. It is thus to be interpreted as
specifying the presence of the stated features, steps or components
as referred to, but does not preclude the presence or addition of
one or more other features, steps or components, or groups thereof.
Thus, the scope of the expression "a device comprising means A and
B" should not be limited to devices consisting only of components A
and B. It means that with respect to the present invention, the
only relevant components of the device are A and B.
[0049] Throughout this specification, reference to "one embodiment"
or "an embodiment" are made. Such references indicate that a
particular feature, described in relation to the embodiment is
included in at least one embodiment of the present invention. Thus,
appearances of the phrases "in one embodiment" or "in an
embodiment" in various places throughout this specification are not
necessarily all referring to the same embodiment, though they
could.
[0050] Furthermore, the particular features or characteristics may
be combined in any suitable manner in one or more embodiments, as
would be apparent to one of ordinary skill in the art.
[0051] A typical Hatchek process is shown in FIG. 1. A number of
monolayers, in the embodiment shown in FIG. 1, in total four, are
created by four rotating sieve drums (145, 147, 149, 151). They are
picked up and stacked on an endless transport belt 113, being a
water permeable felt or fleece. This felt , after having passed the
fourth rotating sieve drum 151, carries a fiber cement multilayered
slab 101. As the system may continue to rotate, this is de facto an
endless fiber cement multilayered slab. This slab 101, which is
transported in production direction 103, is contacted by the
rotating accumulator roll 117. On this accumulator roll 117, which
according to the invention has a recess 125 in axial direction 121
along at least part of the circumference 127 as shown in FIG. 2, a
plurality of fiber cement multilayered slab layers are accumulated
by rotating the accumulator roll along its axis 119, until the
predefined thickness is obtained. At that moment, the accumulated
slab 133 is cut and taken from the roll 117, and laid down on a
transport device 153. As such an uncured, profiled fiber cement
plate 130 is provided. The uncured, profiled fiber cement plate 130
is further adjusted in dimension, and cured in an appropriate way,
e.g. air cured or autoclave cured as the case may be.
[0052] In a processes according to the invention, at least one of
the sieves, e.g. the first sieve 145, provides a monolayer 105
which has a width W1 which is less than the width of the monolayers
107, 109 and 111, provided by the other sieves 147, 149
respectively 151. The sieves are aligned one to the other in such a
way that on the endless belt 113, the monolayer 105 with the
smallest width W1 is encompassed, or in this case covered, by the
other monolayers, in this embodiment the other three monolayers
107, 109 and 111, which have all a substantially identical width
W2.
[0053] A cross section of the endless fiber cement multilayered
slab 101, obtained on the transport device 113 is shown in FIG. 3.
In transverse direction 115 to the production direction, one
notices that the monolayer 105, laid down first on the transport
device 113, is fully covered by the subsequent monolayers 107, 109
and 111.
[0054] As shown in FIG. 4, several layers of this endless fiber
cement multilayered slab (1001, 1002, 1003 and 1004) are
accumulated on the accumulator roll 117. For each slab, the
monolayer with reduced width (1011, 1012, 1013 and 1014) is
provided within the recess 125, thereby providing an accumulated
slab 133 Once the accumulated slab 133 has reached its desired
thickness, the slab 133 is taken from the accumulator roll 117 and
laid down on a transport device 153 as shown in FIG. 1, thereby
providing an uncured, profiled fiber cement plate 130. The cross
section of this uncured fiber cement plate 130, as shown in FIG. 5,
has already a tapered of beveled edges 1301 and 1302 at both sides
1311 and 1312 in production direction 103.
[0055] Curing the uncured fiber cement plate to provide a profiled
fiber cement plate with tapered of beveled edges may be done by
e.g. air curing or autoclaved curing. Optionally, at both sides
1311 and 1312, the plate can be cut to the required total width as
is usually done in Hatschek production, before curing.
[0056] As shown in FIG. 6a, a top view of a rotating sieve drum
rotating in its slurry containing vat, i.e. sieves 145, 147, 149 or
151 is shown. Each rotating drum 2001 rotates around its axis 2003
in the vat 2005. Along a part of the surface of the rotating drum,
the surface is provided with perforations, or is provided in a wire
net material 2007, forming a sieve. The width of the sieve is the
width W2 of the monolayer which will be formed on the sieve surface
when the slurry is sucked from the outside of the sieve towards the
inner side of the sieve. The cement, filler, fibers and other
material will be retained on the sieve surface, forming the
monolayer.
[0057] For the first rotating drum sieve 145 in production
direction 103, at both ends in axial direction, a zone 2009 and
2010 of the sieve is covered by a water impermeable coating, such
as a paint. As such, the monolayer build on this sieve will not
build along the covered zones 2009 and 2010, hence resulting in the
fact that a monolayer with smaller width W1 will be formed.
[0058] It is understood that also alternative sequences, with the
sieve drum 145 positioned not in the first station but in one of
the second, third or fourth position in the rotating drum sieve
train can be used.
[0059] As an example, four rotating drum sieves as shown in FIGS. 1
and 6 are used to form four monolayers. The first monolayer has a
width W1 of 1100 mm, the three subsequent monolayers have a with W2
of 1400 mm. The density and composition of the slurry used to
provide all four monolayers are identical. The composition of the
slurry used is a typical fiber cement slurry comprising water,
cement, cellulose fibers, sand and the typical additives. The
thicknesses of the monolayers are identical and are 0.25 mm.
[0060] As such a fiber cement multilayered slab 101, as shown in
FIG. 3, is provided wherein the first monolayer is covered by the
three other monolayers. The three other monolayers extend over the
first monolayer over a width W3 being, in this sample 150 mm on
both sides.
[0061] This a fiber cement multilayered slab 101 is accumulated on
an accumulation roll 117 with a maximum diameter Dmax of 875 mm,
and having a trapezoid-like recess of depth R of 2 mm and a length
L of the legs in axial direction of the drum 117 of 15 mm. The
minimum diameter Dmin along the recess is 871 mm. So in a zone of
length L, the diameter of the accumulator roll gradually changes
from Dmin to Dmax.
[0062] The accumulator roll, with an approximate circumference of
2750 mm is provided with this recess along 2600 mm, leaving a zone
128 of the circumference with length of 150 mm without recess.
[0063] This absence ensured the fresh slab 101 to be picked up by
the accumulator roll immediately after removal of the previous
accumulated slab.
[0064] In an alternative process, the accumulator roll has a recess
along its complete circumference, while the installation comprises
a means to contact the fresh slab to the accumulator roll
immediately after removal of the previous accumulated slab. E.g air
jets at the end of the transport belt 113, bowing the slab upwards
to the accumulator roll, or vacuum sucking holes in the accumulator
roll may lift the fresh slab towards the accumulator roll. A
moveable roll fitting within the recess and contacting it with his
circumferential surface can be used as well.
[0065] 5 fiber cement products with tapered edges were made, with 5
different thicknesses (6.5 mm, 7 mm, 8 mm, 8.5 mm and 9.5 mm). 6,
7, 8, 9, respectively 10 layers of slab are accumulated on the
accumulator roll to provide the accumulated slab. This accumulated
slab is cut and laid down on the transport device. The uncured,
profiled fiber cement plate obtained have a width 1400 mm, a
maximum thickness of 6.5 mm, 7 mm, 8 mm, 8.5 mm and 9.5 mm and a
minimum thickness at the thinner end of the beveled edge of 4.5 mm,
5 mm, 6 mm, 6.5 mm and 7.5 mm.
[0066] The density profiles of the uncured, profiled fiber cement
plate is shown in FIG. 8. On 5 positions, the density of the
uncured, profiled fiber cement plate was measured. Position P3 is
in the middle of the uncured, profiled fiber cement plate in
transversal direction. P2 and P4 are at 1/4 th of the width of the
uncured, profiled fiber cement plate measured from the respective
edges. P1 and P5 are at the tapered edges of the uncured, profiled
fiber cement plate.
[0067] The uncured, profiled fiber cement plate is reduced to the
commercial width at both sides of the beveled edge profile, is air
dried and hence a profiled fiber cement plate is provided.
[0068] As an alternative set up shown in FIG. 7, for the first
rotating drum sieve 145 in production direction 103, at both ends
in axial direction, a zone 2009 and 2010 of the sieve sprayed by a
water spraying device 2020, spraying water 2022 to the zones 2009
and 2010. The monolayer build in this zone is sprayed away from the
sieve, forming a monolayer with smaller width W1. This has the
advantage that the width of the monolayer can be varied in time,
i.e. for providing the first layer of multilayered slab, the
sprayers can be activated, hence a multilayered slab comprising a
monolayer with reduced with can be provided and accumulated, while,
for the all or some of the consecutive accumulated layers on the
accumulator roll, the sprayers can be deactivated, providing
multilayered slabs consisting of monolayers with all identical
widths.
[0069] It is understood that, in line with the invention, more or
less than four, but at least 2 monolayers can be offered and
accumulated on the accumulator roll. Also that the order of more
wide and less wide monolayers may be varied. Also that that stacks
of monolayers having mutually different widths may be used. Some
alternative cross sections of the endless fiber cement multilayered
slab are shown in FIGS. 9a to 9j, wherein 91, 92, 93, 94, 95 and 96
are monolayers stacked to provide an endless fiber cement
multilayered slab 900 according to the present invention.
[0070] It is to be understood that although preferred embodiments
and/or materials have been discussed for providing embodiments
according to the present invention, various modifications or
changes may be made without departing from the scope and spirit of
this invention.
* * * * *